122 EVOLUTION, OLD AND NEW. 



he should of all animals present us with the greatest 

 variety in shape, stature, colour, and all physical and 

 mental qualities." 



Here again the direct cause of modification is given 

 as being the inner feelings of the animal modified, 

 change of conditions being the indirect cause as with 

 Dr. Erasmus Darwin and Lamarck. 



" Other circumstances, however, concur to produce 

 these results. The dog is short-lived : he breeds often 

 and freely : he is perpetually under the eye of man ; 

 hence when by some chance common enough with 

 Nature a variation or special feature has made its 

 appearance, man has tried to perpetuate it by uniting 

 together the individuals in which it lias appeared, 

 as people do now who wish to form new breeds of 

 dogs and other animals. Moreover, though species 

 were all formed at the same time, yet the number of 

 generations since the creation has been much greater 

 in the short-lived than in the long-lived species : hence 

 variations, alterations, and departure from the original 

 type, may be expected to have become more per- 

 ceptible in the case of animals which are so much 

 farther removed from their original stock. 



" Man is now eight times nearer Adam than the dog 

 is to the first dog for man lives eighty years, while 

 the dog lives but ten. If, then, these species have an 

 equal tendency to depart from their original type, the 

 departure should be eight times more apparent with 

 the dog than with man." * 



Here follow remarks upon the great variability of 

 ephemeral insects and of animal plants, on the impos- 



* Tom. v. pp. 192-195, 1755. 



